This invention relates to a valve assembly and to an internal combustion engine incorporating the valve assembly, wherein the valve assembly has a plurality of valves, each with a valve head supported on a valve stem and a valve seat for receiving the valve head and, more particularly, to a form of construction of the valve assembly wherein the arrangement of the valve stems permits locating a holding tank for engine gasses within a cylinder head of the engine.
One form of valve that is in common use, such as in an automotive engine, has a valve head that rests on a valve seat during a closed position of the valve, the valve further comprising a stem that carries the valve head to and from the valve seat to accomplish a closing and an opening of the valve. As an example in the use of such a valve in the construction of a cylinder head of an internal combustion engine, an intake valve and also an outlet valve located in the cylinder head have this form of construction, namely, a valve head carried by a valve stem with displacement along an axis of the valve stem to lower the valve head onto a seat, formed within the cylinder head, to close the valve; and wherein displacement along the axis of the valve stem in the reverse direction lifts the valve head from the seat to open the valve. The intake valve controls flow of engine gasses between the combustion chamber and an intake manifold, and the outlet (or exhaust) valve controls flow of engine gasses between the combustion chamber and an exhaust manifold, wherein both of the intake and the exhaust manifolds are connected to the cylinder head.
An internal combustion engine of particular interest herein is disclosed in U.S. Pat. No. 6,907,859 issued to B. J. Robinson, the inventor herein. Information on the construction of an engine, disclosed in the Robinson patent, is incorporated herein by reference. In the engine of the Robinson patent, there are further valves in addition to the intake and the outlet valves. The further valves include a return valve and a discharge valve. The return valve closes and opens a passage between the internal space of a cylinder and a holding tank, and the discharge valve closes and opens a passage between the holding tank and a return manifold. In the Robinson patent, the holding tank is formed within an arm of the return manifold, the return valve is located in a return port of the cylinder head at an outboard end of the manifold arm, and the discharge valve is located at the inboard end of the manifold arm adjacent to a central chamber of the return manifold. In the Robinson patent, the function of the holding tank, in conjunction with the additional valves and the return manifold, is to give the engine an elevated expansion ratio while simultaneously being able to reduce the compression ratio for additional fuel savings.
Other examples of engines employing additional manifolds and valves are presented in Date, U.S. Pat. No. 3,878,826, and Amano, U.S. Pat. No. 4,192,265.
In order to facilitate construction of an engine requiring the holding tank and additional valves, such as the engine of the Robinson patent, it is believed that it would be advantageous to reconfigure the cylinder head to include within the cylinder head, in addition to the intake and the outlet valves, also the return and the discharge valves with the holding tank. This would enable these components of the engine to be assembled as part of the cylinder head, and then the completed cylinder head would be joined to the cylinder block, the three manifolds (intake, exhaust and return), and other parts of the engine system.